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A006758
Number of strictly 2-dimensional one-sided polyominoes with n cells.
(Formerly M4114)
4
0, 0, 0, 1, 6, 17, 59, 195, 703, 2499, 9188, 33895, 126758, 476269, 1802311, 6849776, 26152417, 100203193, 385221142, 1485200847, 5741256763, 22245940544, 86383382826, 336093325057, 1309998125639, 5114451441105, 19998172734785, 78306011677181, 307022182222505, 1205243866707467, 4736694001644861, 18635412907198669
OFFSET
0,5
COMMENTS
A000988 is the main entry for this sequence.
This version counts only polyominoes that are strictly 2-dimensional - it excludes those where all the squares are in a single line. Thus a(n) = A000988(n) - 1. - John Mason, Feb 18 2021
The value of a(11) in Table 1 (p. 366) of Lunnon (1975) is incorrect, and was corrected here by N. J. A. Sloane in 2011. - Petros Hadjicostas, Jan 11 2019
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
N. J. A. Sloane, Table of n, a(n) for n = 0..45 [a(0)=0 inserted by Georg Fischer, Jun 25 2020]
W. F. Lunnon, Counting multidimensional polyominoes, Computer Journal 18 (4) (1975) 366-367.
CROSSREFS
A000988 (= a(n) + 1) is another version. A column of A195738.
Sequence in context: A109311 A151350 A195741 * A363165 A123189 A219847
KEYWORD
nonn
EXTENSIONS
Edited by N. J. A. Sloane, Sep 23 2011
a(0)=0 inserted by Sean A. Irvine, Jun 24 2020
Name clarified by John Mason, Feb 18 2021
STATUS
approved